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Old_blaggard
Tinkerer
Username: Old_blaggard
Post Number: 1
Registered: 08-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, August 14, 2010 - 10:31 pm: | 
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Hi everyone, I'm new both around here and to vintage photography in general.
I recently snared myself the Zeiss Ikon Nettar with an f/3.5 lens and a Compur-rapid shutter that goes up to 1/400s. By and large the camera is in pretty good shape, but I would like to make sure it's in the best shape possible for when I start shooting with it. Here's a list of some questions I have:
Shutter.
The shutter has a constant speed, no matter whether the setting it at 1 second or 1/200th. All of the indicated speeds within that range run at about 1/30th of a second. It's only when I push it to the indicated 1/400th that I get a faster response time, and even then it doesn't quite look fast enough; my guess would be somewhere between 1/100th and 1/200th.
I've read that a bit of shutter cleaning should clear this up; however, the is no obvious way to remove the lens from the shutter. Does anyone have any advice on how to do that, and then also on what techniques I should use while cleaning the shutter?
Lens.
Similarly, I would like to get in and clean the lens a bit. The front element was easily unscrewed and I got a fair bit of dust and gunk out of it. However, on the inner surface of the element behind the front, there is a bit of gunk, and the inside of the rear element is rather fogged. Has anyone here ever opened this lens before? If so, could you help me figure out what to do?
Focusing.
Finally, the camera seems to have lost any markings that show where the focus is. The focus ring still has markings from 5ft to inifinity, but there is no line or indicator on the non-rotating part of the lens to reference where I should be taking focus from. If anyone else has this camera, I would love to see a picture to know where I should put my mark.
Finally, just a shot in the dark: does anyone recommend any vintage camera repair shops in the Twin Cities area of Minnesota? If any of these steps requires more than unscrewing a few parts, I would rather have a professional check this out.
Check out the camera at http://www.craftycarpenter.com/nettar/nettar.jpg |
Tylerwebb
Tinkerer
Username: Tylerwebb
Post Number: 24
Registered: 07-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, August 14, 2010 - 11:46 pm: |
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http://www.davidrichert.com/zeiss_521_16_compur_rapid_shutter.htm
This covers all of that pretty well. The shutter speeds part will probably be the hardest, as you will probably have to do lots of fiddling.
Just make sure to work very slowly. Take photos at each stage detailing the important orientation and alignment of everything. Keep everything seperate, and avoid working in a room with carpet on the floor, as it will gobble small bits relentlessly (ideally don't drop anything anyway, but especially on carpet).
Focus calibration can be achieved by winding a 6cm wide piece of wax or parchment paper onto a 120 film roll, and then tightly connecting it from the left-right side just as if it is a roll of film. Make sure its tight! Then using the B setting and a cable release (or T if it works), and the widest aperture, and the back off so you can see the tight wax paper surogate, then hold the camera up to well lit objects and calibrate the focus accordingly. |
Old_blaggard
Tinkerer
Username: Old_blaggard
Post Number: 2
Registered: 08-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, August 15, 2010 - 12:25 am: |
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Thanks for the link. That guy does indeed go through most of my problems, and things do look similar on the lens.
Apparently my second element is *very* stuck, and my infinity focus stop appears to have been shorn off by a previous owner, so I'll have to proceed carefully when re-setting focus and perhaps attach a little marker and stop on my own.
He didn't talk very much about how he got his second element unstuck; do you have any recommendations for where to start? My guess is that spraying WD40 over everything would be a bad idea. |
Tylerwebb
Tinkerer
Username: Tylerwebb
Post Number: 25
Registered: 07-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, August 15, 2010 - 10:37 am: |
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I have a camera with a very similar lens and the same shutter, compur-rapid. My rear element was very very easy to take out, unscrewed. I used a home-made spanner wrench, really just a pair of needle nose pliers with the tips filed down to screwdriver shapes.
I haven't dealt with a stuck element like this, but a few drops of lighter fluid on the threads, has helped me to unstick many screws that wouldn't have budged otherwise. Be very careful of the glass. It's easy to slip...
Never WD-40, don't let that near an old camera! It is made up of 2 parts, and just like cream rises to the top of milk, some chunky gunk seperates out and jams everything after a while.
My first ever camera repair I used WD-40 and it worked great at first. After I let it sit for a week or so, however, it was gummed up and I had to do it all over again.
Is your infinity stop a tiny screw? I'm not sure about this, but its an idea:
What about using a tiny tiny drill-bit (smaller diameter than the stop-screw) to drill out the screw without damaging the threads? Then replace it with a similar enough little screw. I've done this with a large bolt which I broke the head off. |
John_s
Tinkerer
Username: John_s
Post Number: 27
Registered: 07-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Sunday, August 15, 2010 - 01:20 pm: |
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Are you trying to remove the middle element? It's not usually necessary to remove this, just unscrew the front and rear elements and clean the central element in situ through the open shutter / aperture, using a q-tip. If the rear element won't unscrew it may be necessary to remove the lens/shutter from the body. In a very stubborn case where there were no slots to engage, I have carefully cut two slots in the lens outer ring opposite each other with a small hacksaw, (with the assembly out of the camera) then used a metal plate to engage the slots and unscrew the lens. After painting over the slots with matt black, you would not have known they weren't original. |
Old_blaggard
Tinkerer
Username: Old_blaggard
Post Number: 3
Registered: 08-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Monday, August 16, 2010 - 03:47 pm: |
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Thanks again for the responses.
I took the camera into the shop at the local college and got to use some of their tools. I unscrewed the lens elements and gave them a good going-over with optical cleaner and q-tips (good tip, John!). Unfortunately, about 20% of the dirt and 50% of the oil fogging the glass is on the inside of two attached elements that appear nearly impossible to separate (they're both snapped/glued into the same mount).
I then opened up the shutter and put in a small amount of lubricant to try to free things up and get the timings back in order, but unfortunately to no avail. Tomorrow afternoon I'll go in again and try to follow the cleaning instructions from David Richert's site to try to get the shutter back up to speed. |
Old_blaggard
Tinkerer
Username: Old_blaggard
Post Number: 4
Registered: 08-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, August 17, 2010 - 05:01 pm: |
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Went in today and disassembled the thing without too much trouble. That guide is really helpful. I discovered that the tips of two of the shutter blades are slightly dented and will have to be sanded, pressed, and/or clipped to guarantee a smooth run and fully closed shutter. The rest of the clockwork is resting overnight in lighter fluid, and tomorrow I hope to go in, put everything back together, nail down some focus points, and have a smoothly functioning Nettar! |
Tylerwebb
Tinkerer
Username: Tylerwebb
Post Number: 28
Registered: 07-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, August 17, 2010 - 06:44 pm: |
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Great, let us know when its done! Will the clipping of the aperture blades cause the hole to be shaped differently at all? This will effect the shape of your circle of confusion, which could be interesting if it ends up oblong or something. It will potentially increase your aperture setting though, so be sure to consider this when exposing. |
Old_blaggard
Tinkerer
Username: Old_blaggard
Post Number: 5
Registered: 08-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, August 17, 2010 - 09:39 pm: |
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I'll be clipping off the tips of the shutter blades, not the aperture blades, so I hope I won't have that problem. I'll try to get a picture tomorrow through the microscope at the shop to get details of their rips, and of course I'll post my in-progress photos online once I get a chance ;). |
Old_blaggard
Tinkerer
Username: Old_blaggard
Post Number: 6
Registered: 08-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, August 19, 2010 - 03:07 pm: |
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Haha! Got the shutter working today, but the shop was closing so I had to head out before I could reassemble the camera. Looks like I'll have it ready to go for the weekend, though!
Next week there's also a chance that I'll be able to work with the lab manager to set up a laser timer, so that I'll be able to get the exact shutter timings and make any necessary adjustments. Test-firing the shutter made me feel that they were quite close, though. |
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